Feasibility of Ramming Erosion Area of Earthen Sites Using Solidified Soil Induced by An Ancient Curing Agent, Calcined Ginger Nuts

In northwestern China, the earthen sites is threatened because of environmental hazards, such as wind erosion, water erosion, and so on. Rammed reinforcement of the erosion area can improve the overall stability of the site. The formation of the ramming area is a new surface, and new interface between the ramming area and the original site is formed. Therefore, ramming area must meet principle of "repairing the old as the old" and maintain compatibility with the original earthen sites in terms of soil strength, permeability. Calcined ginger nuts (CGN) is an environment-friendly and inorganic material that is emerging curing agent to reinforce the erosion area of the earthen site, which may make the reinforcement area to meet the above requirements. A series of tests were performed to verify its feasibility and investigate its solidified effects and mechanism. The study demonstrated that, with dosage and curing time increasing, the shear strength and unconfined compressive strength of solidified samples slightly improved and the permeability coefficient decreased with a small extent, the disintegration and shrinkage rate significantly decreased, and the total color difference value of samples increased as the sample became brighter. Furthermore, the mechanism of solidified soil has been studied by performing mercury injection, X-ray diffraction (XRD), and scanning electron micrograph (SEM) tests under 25% dosage, which is proposed as the optimum dosage. The pore size decreased with increase of curing time as calcium carbonate content increased. Crystal type of calcium carbonate is mainly calcite—a material with high strength and cohesiveness. Thus, carbonation is the dominant reaction during the curing stage. Moreover, the crystal morphology of calcite changes from needle-stick calcite to flake. In conclusion, CGN can be used as curing agent for reinforcing the erosion area of earthen sites.

在中国西北部，土遗址面临着诸如风力侵蚀、水力侵蚀等环境危害的威胁。对侵蚀区域的夯实加固能够提升该区域的整体稳定性。夯实区域的形成造就了新的地表，以及夯实区域与原始遗址之间的新界面。因此，夯实区域必须遵循‘修旧如旧’的原则，并在土壤强度、渗透性等方面与原始土遗址保持相容性。碳化姜汁坚果（CGN）作为一种环保的无机材料，正逐渐成为一种用于加固土遗址侵蚀区域的固化剂，其可能使加固区域满足上述要求。一系列试验被实施以验证其可行性，并探究其固化效果及机理。研究显示，随着剂量和固化时间的增加，固化样品的剪切强度和无侧限抗压强度略有提升，渗透系数有所降低，样品的崩解率和收缩率显著降低，且随着样品的亮度提升，总色差值也随之增加。此外，通过25%剂量的汞注入、X射线衍射（XRD）和扫描电子显微镜（SEM）测试研究了固化土壤的机理，该剂量被提议为最佳剂量。随着固化时间的增加，孔隙尺寸减小，碳酸钙含量增加。碳酸钙的晶体类型主要为方解石——一种具有高强度和粘结性的材料。因此，在固化阶段，碳化反应占据主导地位。此外，方解石的晶体形态从针状方解石转变为鳞片状。综上所述，CGN可作为固化剂用于加固土遗址的侵蚀区域。